1) Field of the Invention
The present invention relates to a lubricant applying unit, a process cartridge, and an image forming apparatus.
2) Description of the Related Art
Conventionally, an image forming apparatus employs an image forming process of an electrophotographic method to form an image. A toner image is formed on an image carrier (such as a drum-like photosensitive element and a belt-like intermediate transfer body) charged by a charging unit the toner image is transferred onto a recording medium. A cleaning blade is abutted on the surface of the image carrier after the transfer of the toner image to remove the residual toner remaining on the surface of the image carrier.
Since the cleaning blade is abutted on the surface of the image carrier, the image carrier and the cleaning blade are worn out with use over time. Therefore, it is desirable that a lubricant is supplied onto the surface of the image carrier to relief friction on the surface of the image carrier.
A method for supplying the lubricant is disclosed in, for example, Japanese Patent Application Laid-Open No. H7-210051 and Japanese Patent Application Laid-Open No. 2001-51550. A cleaning brush that comes in contact with the surface of the image carrier rotates around the axis. A solid lubricant is abutted on a circumference of the cleaning brush, so that some lubricant rubbed off from the solid lubricant by the cleaning brush is applied on the surface of the image carrier.
As the lubricant, zinc stearate is generally used. The zinc stearate is likely to adhere to the charging unit. When the zinc stearate adheres on the charging unit, resistance of the entire charging unit can be changed. As a result, charge in the charging unit may become insufficient. It is not possible to suppress the adhesion of the lubricant to the charging unit with the techniques disclosed in the above patent literatures.
If the charging unit is not sufficiently charged, image quality is degraded because the image carrier cannot be uniformly charged. If the zinc stearate is used as the lubricant, the insufficient charge frequently occurs, and consequently, frequent maintenance to remove the adhered lubricant becomes necessary to keep the image quality. This shortens a lifetime of the charging unit.